Coated nickel titanium archwires and their uncoated counterparts: In-vitro contemporary comparison of unloading forces.

OBJECTIVE: To compare the unloading forces between aesthetic nickel titanium (NiTi) wires coated with rhodium and epoxy resin, as well as their uncoated equivalents. Additionally, intragroup comparisons between the different deactivation forces were evaluated, and the inner alloy cores were determined. MATERIAL AND METHODS: Forty-four 0.018" NiTi wire segments were equally divided into 4 groups: E- NiTi coated with epoxy resin, C- NiTi uncoated, R- heat-activated NiTi coated with rhodium, and T- heat-activated NiTi uncoated. The unloading values were recorded at 0.5, 1, 2, and 3mm using a 3-point bending test, according to the method in ISO Standard 15.841. Cross-sectional scanning electron microscopy was used to assess the inner alloy core thickness of the wires. RESULTS: The intergroup comparison was successively: at 0.5mm: E (1.21)>C (0.60)=R (0.63)=T (0.58); at 1mm: E (1.30)=C (1.23)>R (0.91)=T (0.80); at 2mm:C (1.93)>E (1.36)=R (1.20) and R (1.20)=T (1.00) and E (1.36)>T (1.00); at 3mm:C (2.44)>R (2.02)>E (1.62)=T (1.68). The intragroup comparisons showed for all groups that the forces were statistically higher at 3mm than the other deactivations (p<0.01). Group E presented a reduced inner alloy core (.0155). CONCLUSION: The unloading forces demonstrated variability between the wires tested and between the different deactivations. Therefore, depending on the type of movement required and the periodontal conditions, orthodontists should pay attention during archwire selection.

Comparison of gingival display in smile attractiveness among restorative dentists, orthodontists, prosthodontists, periodontists, and laypeople.

STATEMENT OF PROBLEM: Multidisciplinary treatment needs a common goal, and dentists should understand the esthetic perception of laypeople and the other specialists involved. Such information is sparse. PURPOSE: The purpose of this cross-sectional study was to compare the influence of gingival display on perceived smile esthetics among restorative dentists, orthodontists, prosthodontists, periodontists, and laypeople. MATERIAL AND METHODS: Photographs of the smiles of 2 volunteers (1 female and 1 male) were manipulated on a computer to produce gingival exposure of 1, 3, and 5 mm and central incisor coverage of 3 and 5 mm. The images were evaluated by using a 100-mm visual analog scale by 155 raters divided into 5 groups (restorative dentists, orthodontists, prosthodontists, periodontists, and laypeople). RESULTS: The dental specialists, mainly orthodontists and periodontists, were more sensitive about alterations in gingival display than the laypeople. For the female smile, higher mean scores were attributed to 1 mm of gingival exposure by all groups of raters. For the male smile, 3 mm of central incisor coverage received higher mean scores, except for the laypeople, who considered gingival display of 1 mm to be more attractive. For both smiles, 5 mm of gingival display was judged to be the least attractive. CONCLUSIONS: Considering the differences in opinion between dental specialists and laypeople and the acceptable variations in gingival display, the preferences of patients should be considered in the diagnosis and treatment decision-making process.

Intrusion of maxillary molar using mini-implants: A clinical report and follow-up at 5 years.

This clinical report describes a straightforward alternative treatment for adult patients with extruded maxillary molars, who are reluctant to use fixed appliances and complex mechanics. The maxillary molar supereruption of a 57-year-old woman was treated using buttons bonded to the buccal and palatal surfaces of the molars, 2 mini-implants, and elastomeric chains. The intrusion was achieved in 5 months. The treatment stability was observed for 5 years after treatment.

Two-Year Follow-up of Multidisciplinary Treatment Using Digital Smile Design as a Planning Tool for Esthetic Restorations on Maxillary Midline Diastema.

One of the challenges posed by diastema closure treatment in the presence of tooth size discrepancy is to achieve adequate distribution of the spaces between the teeth. The use of the Digital Smile Design can assist the clinician in visualizing and measuring dentogingival discrepancies with maximum predictability. The present clinical case describes an approach to space distribution with assistance of the digital tool, allowing adequate restorative procedures. The protocol used was shown to be efficient, achieving the esthetics desired by the patient both during and after multidisciplinary treatment, as well as having adequate stability.

Evaluation of an alternative technique to optimize direct bonding of orthodontic brackets to temporary crowns.

OBJECTIVE: To compare shear bond strength of different direct bonding techniques of orthodontic brackets to acrylic resin surfaces. METHODS: The sample comprised 64 discs of chemically activated acrylic resin (CAAR) randomly divided into four groups: discs in group 1 were bonded by means of light-cured composite resin (conventional adhesive); discs in group 2 had surfaces roughened with a diamond bur followed by conventional direct bonding by means of light-cured composite resin; discs in group 3 were bonded by means of CAAR (alternative adhesive); and discs in group 4 had surfaces roughened with a diamond bur followed by direct bonding by means of CAAR. Shear bond strength values were determined after 24 hours by means of a universal testing machine at a speed of 0.5 mm/min, and compared by analysis of variance followed by post-hoc Tukey test. Adhesive remnant index (ARI) was measured and compared among groups by means of Kruskal-Wallis and Dunn tests. RESULTS: Groups 3 and 4 had significantly greater shear bond strength values in comparison to groups 1 and 2. Groups 3 and 4 yielded similar results. Group 2 showed better results when compared to group 1. In ARI analyses, groups 1 and 2 predominantly exhibited a score equal to 0, whereas groups 3 and 4 predominantly exhibited a score equal to 3. CONCLUSIONS: Direct bonding of brackets to acrylic resin surfaces using CAAR yielded better results than light-cured composite resin. Surface preparation with diamond bur only increased shear bond strength in group 2.

Evaluation of an alternative technique to optimize direct bonding of orthodontic brackets to temporary crowns

OBJECTIVE: To compare shear bond strength of different direct bonding techniques of orthodontic brackets to acrylic resin surfaces.METHODS: The sample comprised 64 discs of chemically activated acrylic resin (CAAR) randomly divided into four groups: discs in group 1 were bonded by means of light-cured composite resin (conventional adhesive); discs in group 2 had surfaces roughened with a diamond bur followed by conventional direct bonding by means of light-cured composite resin; discs in group 3 were bonded by means of CAAR (alternative adhesive); and discs in group 4 had surfaces roughened with a diamond bur followed by direct bonding by means of CAAR. Shear bond strength values were determined after 24 hours by means of a universal testing machine at a speed of 0.5 mm/min, and compared by analysis of variance followed by post-hoc Tukey test. Adhesive remnant index (ARI) was measured and compared among groups by means of Kruskal-Wallis and Dunn tests.RESULTS: Groups 3 and 4 had significantly greater shear bond strength values in comparison to groups 1 and 2. Groups 3 and 4 yielded similar results. Group 2 showed better results when compared to group 1. In ARI analyses, groups 1 and 2 predominantly exhibited a score equal to 0, whereas groups 3 and 4 predominantly exhibited a score equal to 3.CONCLUSIONS: Direct bonding of brackets to acrylic resin surfaces using CAAR yielded better results than light-cured composite resin. Surface preparation with diamond bur only increased shear bond strength in group 2.

OBJETIVO: comparar a resistência ao cisalhamento de diferentes técnicas para colagem direta de braquetes ortodônticos em superfície de resina acrílica.MÉTODOS: sessenta e quatro (64) discos de resina acrílica ativada quimicamente (RAAQ) foram divididos aleatoriamente em qautro grupos: grupo 1 = colagem com resina composta fotopolimerizável (adesivo convencional); grupo 2 = superfície abrasionada com broca diamantada e colagem com resina composta fotopolimerizável; grupo 3 = colagem com RAAQ (adesivo alternativo); grupo 4 = superfície abrasionada com broca diamantada e colagem com RAAQ. A resistência ao cisalhamento foi avaliada 24h após a colagem, utilizando-se uma máquina universal de ensaios, operando a uma velocidade de 0,5mm/min, e comparada por meio da análise de variância, seguida pelo teste post-hoc de Tukey. O índice de adesivo remanescente (IAR) foi mensurado e comparado entre os grupos por meio dos testes Kruskal-Wallis e Dunn.RESULTADOS: os grupos 3 e 4 demonstraram resistência ao cisalhamento significativamente maior do que os grupos 1 e 2. Os grupos 3 e 4 apresentaram resultados similares. O grupo 2 apresentou melhores resultados do que o grupo 1. Na análise do IAR, observou-se predominância do escore 0 para os grupos 1 e 2 e do escore 3 para os grupos 3 e 4.CONCLUSÕES: a colagem do braquete em superfície de resina acrílica utilizando-se a RAAQ apresentou melhores resultados do que a colagem com resina composta fotopolimerizável. A abrasão da superfície com broca diamantada apenas aumentou a resistência ao cisalhamento no grupo 2.

Evaluation of Fracture Resistance of Orthodontic Mini-implants in the Transmucosal Profile Region.

AIM: This study sought to compare the fracture resistance of three trademarked orthodontic mini-implants in the transmucosal profile region. Thirty-six mini-implants of three different brands, separated into groups I, II and III, were tested. Each group consisted of 12 mini-implants of 6 mm in length. The mean diameter and length of the transmucosal profile of the mini-implants were 1.90 and 2.0 mm in group I, 1.77 and 1.0 mm in group II and 1.50 and 1.0 mm in group III, respectively. The tests were performed on a universal testing machine in compression mode, with a 2,000 kgf load, a speed of 4.0 mm per minute and a chisel-shaped active tip, which acted cross-sectionally on the transmucosal profile. Single-criterion analysis of variance was used to compare the three brands. A significance level of 5% and test power of 80% were adopted. The mean fracture resistance achieved by the mini-implants was 172.03 ± 25.59 N for group I, 162.35 ± 30.81 N for group II and 139.69 ± 42.99 N for group III. There was no statistically significant difference in mean fracture resistance among the tested mini-implant brands. CONCLUSION: The transmucosal profile diameter does not seem to be a deciding factor in the choice of mini-implants to minimize the risk of fractures. CLINICAL SIGNIFICANCE: Although being an in vitro study it is possible to believe that this new brand has a very satisfactory resistance to fracture and enables its use with great efficiency.

Correlation between the Rotation of the First Molars and the Severity of Class II Division 1 Malocclusion.

This study aimed to evaluate the potential correlation between the severity of Class II division 1 malocclusion and the magnitude of mesiopalatal rotation of the maxillary first molars. Scanned images of 104 cast models were grouped according to the severity of Class II malocclusion as follows: Group 1, 1/4 Class II malocclusion; Group 2, 1/2 Class II malocclusion; Group 3, 3/4 Class II malocclusion; and Group 4, complete Class II malocclusion. The rotation was measured using parameters described by Henry, Friel, and Ricketts, referred to as indicators 1, 2, and 3, respectively. The correlation was evaluated using the Spearman's correlation coefficient. The rotational indicators were compared using one-way analysis of variance. For all statistical analyses used p < 0.05, a positive correlation was observed between the severity of Class II malocclusion and the mesiopalatal rotation of the maxillary first molar. This correlation was statistically significant for indicator 1 between Groups 1 and 3 and for indicator 2 between Groups 1 and 4, which include cases of extreme malocclusion. In conclusion, there is a positive correlation between the severity of Class II division 1 malocclusion and the magnitude of mesiopalatal rotation in the maxillary first molars.

Can Whitening Strips interfere with the Bond Strength of Composite Resins?

AIM: The aim of this study was to investigate in vitro the bond strength of composite resins on enamel previously treated with whitening strips. MATERIALS AND METHODS: A total of 48 bovine incisors were allocated to four experimental groups (n = 12 each): G1 (WSC)- treated with 9.5% hydrogen peroxide whitening strips (3D White Whitestrips® Advanced Vivid/CREST); G2 (WSO)-treated with 10% hydrogen peroxide whitening strips (3D WhiteTM/Oral B); G3 (WG)-treated with 7.5% hydrogen peroxide gel with fluorine, calcium and potassium nitrate (White Class®/FGM); and G4 (C)-control not subjected to bleaching treatment. The specimens were subjected to bleaching over 2 weeks following the manufacturers' instructions. Following the elaboration of the composite resin test specimens, the samples were stored in artificial saliva and subsequently subjected to the micro-shear test using the universal testing machine (EMIC®). The bond strength values were analyzed by one-way ANOVA and Tukey's statistical test (5%). RESULTS: Significant differences were observed among the investigated groups (p < 0.05). The G3-WG exhibited greater values compared with the control group and the groups treated with strips, G1-WSC and G2-WSO. Analysis of the bond interface revealed that a large fraction of the failures occurred at the enamel-resin interface. CONCLUSION: The bond strength decreased following 14 days of treatment with bleaching strips, whereas the whitening gel with 7.5% hydrogen peroxide, calcium and fluorine increased the bond strength.

Deflection Evaluation of Thermoactivated Nickel-Titanium Archwires after Heat Treatment on their Distal Ends.

OBJECTIVE: This study evaluated in vitro the mechanical changes of 0.018" (0.45 mm) and 0.016 × 0.022" (0.40 × 0.55 mm) thermoactivated nickel-titanium archwires subjected to heat treatment on their distal ends. MATERIALS AND METHODS: Ten archwires in diameters 0.018" and 0.016 × 0.022" by different manufacturers Ormco, Morelli, Orthometric and Unitek were tested. Each tested archwire had an experimental side, submitted to heat treatment, and an annealing-free control. Tests for load/deflection were performed using a universal testing machine, with temperature control in the austenitic transformation phase through tempe rature-controlled chamber. The variables showed normal distribution (Kolmogorov-Smirnov), the t-student test was applied in order to observe the difference between the experi mental and control groups. Statistical significance was set at p < 0.05. RESULTS: There were no statistically significant differences between the groups. CONCLUSION: Heat treatment carried out in the region corresponding to the first molar distal region on thermoactivated nickel-titanium archwires did not influence the load/deflection values in adjacent portion.

Tratamento da má oclusão Classe II, 2º divisão, com desvio de linha média com aparelho de protrusão mandibular unilateral / Treatment of Class II division 2 malocclusion with dental line deviation using unilateral mandibular protraction appliance

A Classe II é uma má oclusão muito frequente na população que procura o tratamento ortodôntico. Pode ser caracterizada por um desequilíbrio das estruturas dentárias e/ou esqueléticas. Dentre as opções para o tratamento desta má oclusão podemos citar o aparelho de protração mandibular (APM) que propicia alterações esqueléticas e/ou dentoalveolares. Sendo assim, este artigo se propõe expor um caso clínico de paciente portadora de má oclusão de Classe II, 2ª divisão, tratada com o APM unilateral para correção dentária e do desvio de linha média inferior.

The treatment of Class II malocclusion is frequent in seeking patients orthodontic treatment. This malocclusion is characterized by dental or skeletal disorders. Among the treatment options, the mandibular protraction appliance (MPA) is an alternative that provides skeletal and/or dentoalveolar changes. There fore this article aimed at presenting a case report of Class II division II malocclusion treated with unilateral mandibular protraction appliance for dental correction and lower midline deviation.

Avaliação hodierna da aplicabilidade da classificação das más-oclusões de Angle / Currently applicability of Angle's malocclusion classification

Este estudo teve como principal objetivo avaliar o uso, naatualidade, da classificação de Angle, por 37 especialistas em Ortodontia.Para essa finalidade, foi utilizado um questionário, composto de três fotosque abrangiam apenas as relações entre os dentes posteriores, sendoque, nos três casos, a relação molar apresentada era de Classe I. Oexaminador deveria obedecer à classificação da máoclusão de Angle. Naavaliação do questionário, verificou-se que aproximadamente 69% dosexaminadores classificaram o relacionamento anteroposterior entre osmolares como Classe I, enquanto que 28% apontaram ser Classe II,e 3%apontaram ser Classe III.Entre os examinadores, 27% afirmaram utilizarapenas a classificação de Angle para fins de diagnóstico, concluindo que73% não utilizam apenas o referido sistema para a mesma finalidade. Oestudo mostrou que grande parte dos profissionais avaliados conheceos conceitos de Angle, embora não os utilize como única forma dediagnóstico de má-oclusão, priorizando outros métodos.

The aim of this study was to evaluate the use, innowadays, of the Angle classification by 37 orthodontists. For thispurpose, a questionnaire was used, consisting of three photos, coveringonly the relations between the posterior teeth, whereas in all threecases, the molar relation was Class I, which the examiner should haveclassified as the malocclusion of Angle. In the assessment questionnaire,it has been found that approximately 69% of examiners classified theanteroposterior relationship between molars as Class I, while 28%indicated as Class II and 3%, as Class III. Among the examiners,27% reported to use only the Angle classification for the diagnose,thus concluding that 73% do not use only this system for the samepurpose. This study showed that most assessed professionals know theconcepts of Angle, but do not use it as the only way for the diagnosisof malocclusion, prioritizing other methods.

Distalization of maxillary molars using a lever arm and mini-implant.

This article describes the orthodontic treatment of a young woman with a Class II malocclusion and maxillomandibular prognathism. One orthodontic mini- implant was placed in the posterior area of the palate to provide anchorage for?a transpalatal arch. The force for molar distalization was applied using an elastic chain from the lever arm inserted on the transpalatal arch to the mini-implant. Two sliding jigs were applied buccally as a complement for Class II malocclusion correction. This system created an efficient mechanotherapy for maxillary molar distalization. The active treatment period was 19 months. Normal overjet and reduction of maxillomandibular prognathism were obtained, and labial balance was improved.

Utilização dos mini-implantes ortodônticos como elemento protético e de ancoragem em casos de agenesia dos incisivos laterais superiores permanentes / Orthodontic mini-screwa used as prosthetic element and anchorage in cases of agenesis of permanent lateral maxillary incisors

Para a adequação de espaços edêntulos, principalmente na região anterior das arcadas dentárias, torna-se importante minimizar os efeitos colaterais nas unidades de ancoragem durante a movimentação ortodôntica e, consequentemente, promover a estética e função ao longo do tratamento. O objetivo desse trabalho é apresentar a versatilidade dos mini-implantes em atender a esses objetivos, por meio de um caso clínico com agenesia dos incisivos laterais superiores permanentes, em que a estratégia terapêutica envolveu a reposição protética na área.

Tratamento da mordida aberta esquelética em adultos com a técnica Multiloop Edgewise Archwire / Skeletal anterior open bite treatment in adults by Multiloop Edgewise Archwire technique

O tratamento da mordida aberta anterior em pacientes adultos apresenta muitas limitações. A terapia cirúrgica é a mais adequada para esses casos; no entanto, por razões psicológicas, alguns pacientes rejeitam essa forma de tratamento. Diante da necessidade de tratamento desses pacientes, esse artigo se propõe a apresentar um caso de mordida aberta anterior severa tratada com a técnica Multiloop Edgewise Archwire (MEAW). Ao final do tratamento foi atingida oclusão ideal, com função adequada e estética agradável, demonstrando que a técnica aplicada foi efetiva para a correção da mordida aberta anterior, sem cirurgia.

Análise comparativa da relação carga/deflexão entre fios de níquel-titânio convencionais e estéticos / Comparative study of load/deflection property between regular nickel-titanium wires and aesthetic wires

O objetivo deste estudo foi avaliar, comparativamente, a relação carga/deflexão dos fios ortodônticos de níquel-titânio superelásticos metálicos e estéticos, das marcas Orthometric® e GAC-Dentsply®. Foram avaliados fios ortodônticos 0,016” de níquel-titânio em arcos pré-contornados, com e sem revestimento. As amostras totalizaram 20 segmentos de fios de 28 mm, divididos em 4 grupos: Grupo 1 - Orthometric – Marília/SP/Brasil – estético, Grupo 2 - Orthometric - metálico superelásticos, Grupo 3 - GAC / Dentsply – New York/NY/USA – estético e Grupo 4 - GAC – Dentsply - metálico superelástico. Foi utilizado como corpo de prova um dispositivo em acrílico com bráquetes metálicos Edgewise slot .022” (Dental Morelli Ltda., Sorocaba/SP/Brasil). O teste de deflexão foi realizado na máquina de ensaio universal Kratos a uma velocidade de 0,5 mm/min, com célula de carga de cinco Newtons, utilizando-se uma ponta com extremidade cônica de 8 mm de diâmetro. A análise da relação carga/deflexão foi mensurada a cada 0,5 mm, entre 0 e 3 mm de deflexão do fio. Os resultados deste estudo demonstraram que não houve diferença estatisticamente significante entre os grupos de acordo com o Teste ANOVA, para a ativação (p= 0,774) e desativação (p=0,367), considerando a = 0,05. Concluí-se que todos os grupos possuem valores da proporção carga/deflexão semelhantes.

The aim of this study was to perform a comparative analysis of the load-deflection relation between coated (aesthetic) and uncoated nickel-titanium orthodontic wires from two different brands: Orthometric® (Marília/SP/Brazil) and GAC-Dentsply® (NewYork/NY/USA). An assessment of nickel-titanium orthodontic wires of 0.016” on pre-countered arches was performed. The sample was composed of 20 segments of 0.016” nickel-titanium orthodontic arches divided into 4 groups: Group 1 - Orthometric® – aesthetic; Group 2 - Orthometric® -superelastic alloy, Group 3 - GAC/ Dentsply – aesthetic; Group 4 - GAC – Dentsply - superelastic alloy. An acrylic device with metal brackets was used as specimen. The deflection test was carried out in a Kratos universal testing machine, at a 0.5 mm/min speed with a 5 Newtons load cell using a 8mm tapered tip. The analysis of the load/deflection relation was measured every 0.5 mm between 0 and 3 mm of wire deflection. The results of this study showed no statistically significant difference between groups according to ANOVA test for the activation (p = 0.774) and deactivation (p = 0.367), considering a = 0.05. It was concluded that all groups have similar values for load/deflection ratio

Determination of the structural characteristics in youngsters from Ceará with Class II, division 1 malocclusion / Determinação das características estruturais em jovens do Ceará com má oclusão de Classe II, divisão 1

OBJECTIVE: To determine the structural characteristics of Caucasian youths from Ceará State, Northeastern Brazil, presenting with Class II, Division 1 malocclusion and to investigate whether there is gender dimorphism based on the cephalometric variables assessed. METHODS: By means of lateral cephalograms, it was possible to determine the cephalometric characteristics of Class II, Division 1 malocclusion in a sample of 50 Caucasian youths from Ceará State, Brazil, of both genders (25 male and 25 female), aged between 9 and 14 years, who had not received previous orthodontic treatment. Sixteen cephalometric measures were evaluated and a comparison was made between the experimental group (Class II) and the control group (Class I), a sample comprising 50 Caucasian children from the Brazilian State of Ceará, of both genders (22 male and 28 female), aged 9 to 13 years, obtained from research conducted at the Study Center of the Federal University of Ceará (UCCB), Department of Orthodontics. CONCLUSIONS: Overall, the maxilla exhibited adequate positioning. The mandible showed a clear predominance of retrusion and dimensional changes in the sagittal direction. The facial vertical dimensions were increased. The maxillary incisors were well-positioned in their apical bases and with slight lingual inclination. The mandibular incisors were labially inclined and protruded. The study identified the presence of gender dimorphism in the following measures: P-Nperp, Co-A, Wits and ALFH.

OBJETIVO: determinar as características estruturais em jovens cearenses leucodermas, portadores de má oclusão de Classe II, divisão 1, e verificar se existe dimorfismo entre os sexos a partir das variáveis cefalométricas estudadas. MÉTODOS: por meio de telerradiografias em norma lateral, determinou-se as características cefalométricas da má oclusão de Classe II, divisão 1, em uma amostra de 50 jovens cearenses, leucodermas, sendo 25 do sexo masculino e 25 do sexo feminino, com idades de 9 a 14 anos, não tratadas ortodonticamente. Dezesseis grandezas cefalométricas foram avaliadas, comparando-se o grupo experimental (Classe II) com um grupo controle (Classe I), cuja amostra constituiu-se de 50 crianças do Ceará, leucodermas,de ambos os sexos (22 do sexo masculino e 28 do sexo feminino), com idades entre 9 e 13 anos, obtida de pesquisas realizadas pela disciplina de Ortodontia da UCCB - Centro de Estudos da Universidade Federal do Ceará. CONCLUSÃO: a maxila apresentou, em média, um bom posicionamento. A mandíbula apresentou uma clara predominância para retrusão e alterações dimensionais no sentido sagital. As dimensões verticais da face apresentaram -se aumentadas. Os incisivos superiores apresentaram-se bem posicionados em suas bases apicais e ligeiramente inclinados para lingual. Os incisivos inferiores protruídos e inclinados para vestibular. Identificou-se a presença de dimorfismo entre os sexos nas grandezas P-Nperp, Co-A, WITS e AFAI.

Abordagens da biomecânica ortodôntica utilizando miniimplantes / Approaches of orthodontic biomechanics using mini-implants

Como inovador dispositivo de ancoragem, os mini-implantes devem ser descritos em relação ao seu uso e modo de atuação durante o tratamento ortodôntico. Assim, pretendemos expor alguns critérios de biomecânica adotados para melhor aproveitamento dos mini-implantes utilizados como ancoragem para a retração anterior (fechamento de espaço), distalização de molares, mesialização de molares, intrusão de molares e como suporte de provisórios.

As an innovative transitory anchorage device, the mini-implants deserve to be described with details regarding its use and action during orthodontic treatment. Therefore, this paper intents to present some biomechanic criteria adopted to for a better use of mini-implants as anchorage in anterior retraction (space closure), molar distalization, mesial movement of the molars, intrusion of molars and as support to provisional implant.

Estudo in vitro da resistência ao cisalhamento da colagem direta de tubos ortodônticos em molares / In vitro study of shear bond strength in direct bonding of orthodontic molar tubes

INTRODUÇÃO: apesar da colagem direta despender menor tempo clínico, com maior preservação da integridade gengival, ainda hoje se observa uma alta incidência de bandagem dos molares. Portanto, torna-se interessante a idealização de recursos para o aumento da eficiência desse procedimento para dentes submetidos a maiores impactos mastigatórios, como, por exemplo, os molares. OBJETIVO: esse estudo teve o propósito de avaliar se a resistência à adesão com a aplicação de uma camada de resina adicional na região oclusal da interface tubo/dente aumenta a qualidade do procedimento de colagem direta de tubos em molares. MÉTODOS: selecionou-se uma amostra composta por 40 terceiros molares inferiores, que foram aleatoriamente divididos em 2 grupos: Grupo 1 - colagem direta convencional, seguida pela aplicação de uma camada de resina na oclusal da interface tubo/dente; e Grupo 2 - colagem direta convencional. O teste de resistência ao cisalhamento foi realizado 24 horas após a colagem, utilizando-se uma máquina de ensaio universal, operando a uma velocidade de 0,5mm/min. Os resultados foram analisados por meio do teste t independente. RESULTADOS: os valores médios obtidos nos testes de cisalhamento foram: 17,08MPa para o Grupo 1 e 12,60MPa para o Grupo 2. O Grupo 1 apresentou uma resistência ao cisalhamento estatisticamente significativa mais alta do que o Grupo 2. CONCLUSÃO: a aplicação de uma camada adicional de resina na oclusal da interface tubo/dente aumenta a qualidade da adesão do procedimento de colagem direta de tubos ortodônticos em molares.

OBJECTIVE: Although direct bonding takes up less clinical time and ensures increased preservation of gingival health, the banding of molar teeth is still widespread nowadays. It would therefore be convenient to devise methods capable of increasing the efficiency of this procedure, notably for teeth subjected to substantial masticatory impact, such as molars. This study was conducted with the purpose of evaluating whether direct bonding would benefit from the application of an additional layer of resin to the occlusal surfaces of the tube/tooth interface. METHODS: A sample of 40 mandibular third molars was selected and randomly divided into two groups: Group 1 - Conventional direct bonding, followed by the application of a layer of resin to the occlusal surfaces of the tube/ tooth interface, and Group 2 - Conventional direct bonding. Shear bond strength was tested 24 hours after bonding with the aid of a universal testing machine operating at a speed of 0.5mm/min. The results were analyzed using the independent t-test. RESULTS: The shear bond strength tests yielded the following mean values: 17.08 MPa for Group 1 and 12.60 MPa for Group 2. Group 1 showed higher statistically significant shear bond strength than Group 2. CONCLUSIONS: The application of an additional layer of resin to the occlusal surfaces of the tube/tooth interface was found to enhance bond strength quality of orthodontic buccal tubes bonded directly to molar teeth.